I've been using racks from Reptilie Basics for the past 4 years now and I love them. The only problem is they warp if you put them on carpet. I don't have the option of not having carpet as I currently rent. Is there something I can do to help stop the warping? I've stopped stacking the racks as this makes the warping worse and I plan on replacing the racks over the next few years. (I long for an ARS rack but man those things are expensive!!)